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HIGH DEFINITION INFRARED
The Truth About What You Thought You Knew
The term HD has become ubiquitous through products
like HD TV, HD radio, even HD sunglasses. Obviously,
the term doesn’t truly apply to all these areas. Further,
because the term has become watered down, HD has
also been inaccurately used to imply a capability that
isn’t actually provided.
“FLIR has been at the forefront of
infrared technology for decades.”
In specialty fields, such as infrared imaging, real HD
video requires numerous HD-capable components, all
designed to seamlessly work together. Some players
in this industry will achieve HD capabilities in one or
another component and use marketing to cover
deficiencies in other areas. This applies to every
player in the thermal imaging industry except one –
FLIR has been at the forefront of infrared technology for
decades; pioneering everything from increased detector
and resolution capability to 3D infrared binoculars. It’s
no different with HD thermal imaging. To understand
high definition in regards to thermal imaging, one must
first understand what they do and do not know.
In the end, no matter what you call it, real HD infrared
image quality speaks for itself.
What Most People Understand
In simplest terms, HD, or high definition, refers to any
video system that has higher resolution than standard
definition – the more pixels, the better the resolution,
the higher the definition. To be accurate, image clarity
is also reliant upon the quality of the pixel itself, but that
level of understanding isn’t required for this discussion.
Low definition pixel resolution
Standard definition pixel resolution
High definition pixel resolution
Most people understand HD, first and foremost, in
terms of their television set. To that end, high definition refers to a pixel count of 1920x1080 (1080p) or
1280x720 (720p), as compared to standard definition,
which is much less. In terms of HD thermal imaging,
resolution is of similar importance, with more total
pixels providing not only greater image clarity, but also
more detailed information on heat gradients across a
body or an object. This is particularly important for
smaller or more distant bodies and objects.
For most people, pixel count is the extent of their understanding of high definition – the bigger the number,
the better the result. However, there is much more to
providing HD quality video than the total number of
pixels. For example, keeping with the television analogy,
if the source video isn’t high definition, it won’t matter
that the TV itself is HD-capable, the standard definition video is all the viewer will see. Likewise, if the video
feed is HD-quality, but the TV only has standard definition resolution, the viewer will still only see standard
definition video. Though the pixel counts that denote
higher definition are the same whether one is discussing
TV or thermal imaging, there is a significant, primary
difference. HD TV deals with displaying HD content.
When generating HD footage, there are many more elements that can drastically affect the quality of the image
viewed beyond the simple display resolution.
HIGH DEFINITION THERMAL IMAGING
More Than One Step Beyond Standard
Like HD TV, an HD thermal image is only as good as
its source. To create a real HD thermal video, all aspects
of the camera must be HD capable – the optics, the detector, the processing electronics, and the interface, not
to mention the actual digital file formats. Beyond the
technical capabilities of the camera components, the
entire system must also be supported by an exceptionally stable gimbal – even more than usual – to ensure a
crisp image without blurring or visible jitter.
High definition thermal imaging requires native high
definition capability not only in the detector, but also
in the optics. Putting a high definition detector behind
standard-definition optics will result in a standarddefinition image. Even with HD capable components,
a full high definition thermal imaging system also requires the high-bandwidth digital information to be
processed in its native format, thus at much higher
speed, to maintain image fidelity. Once that data is captured, it needs to be output in a proper format. Cutting
corners at even one of these steps will degrade the quality of the image and result in data loss.
Real HD thermal imagery begins with the optics. The
function of the lens is to recreate the picture for the sensor. The quality of the lens is a significant arbiter of quality; affecting contrast, sensitivity, and image sharpness.
Lenses designed for standard definition imaging systems only support a limited optical resolution. HD systems are far more demanding. The level of definition a
lens is capable of transmitting is determined by linepair per millimeter (LP/mm). A standard definition
lens resolves at no more than 30 LP/mm. The higher
resolution requires a lens resolving at a minimum of 80
Detector/Focal Plane Array
Data Connector and Cabling
Output or Display
LP/mm. FLIR in-house optics and coatings capabilities
result in significantly superior performance with lens
resolving capabilities exceeding 200 LP/mm.
Once the image is translated through a camera’s lens,
it needs to be captured by a detector. Infrared detectors (or sensors) use focal plane arrays (FPAs) to capture image data. To achieve HD quality, these FPAs
must have either native 640x512 pixel plus optical microscanning or native 1280x720 pixels to achieve full
1280 x 720 (720p) resolution.
Optical microscanning is a technology that increases
the real (native) resolution of the system and prevents
high resolution targets from getting lost. This technique increases range performance while also increasing the brightness and contrast of small targets. FLIR
uses both methods to generate real HD infrared video.
Other IR imaging systems that do not have optical microscanning or real HD FPAs, simply up-convert low
resolution detectors using electronic zoom techniques.
This method will fill in otherwise empty space on a display, but it will not provide any performance benefits.
In essence, this method has the same effect as simply
moving closer to the screen.
Image processing is the next critical step in delivering
a real HD image. The individual bits of data from the
detector must be assembled and the final image constructed, buffered, adjusted for best viewability, and
transmitted through the system to the output interface.
A real HD image has far more data and is much denser
in content than a standard definition image, and all
this processing must be done in real time. This requires
much higher data rates and much more powerful processing electronics, which inevitably generates more
heat within the system. The thermal management of
such a system, to keep it cool at high ambient temperatures, is another daunting challenge in building a reliable HD system.
Once an image is captured and processed, the actual
image quality is related directly to the bandwidth available from the interfaces; the more bandwidth, the more
potential visual resolution. The converse is also true; the
less bandwidth is available, the less detail will be visible.
Maintaining native file size and data formats will result
in a much higher resolution image. If the source video
is compressed in any way for it to be streamed via a low
bandwidth interface, data will necessarily be lost. All
video compression techniques result in an end product
that is no longer high quality HD video.
Uncompressed, native HD video streaming utilizes a
very high data rate which requires a high definition serial digital interface (HD-SDI) or better. These interfaces are referred to by their technical standard names
and are appropriate for different levels of HD resolution: SMPTE-292M for 720p and either SMPTE-372M
or SMPTE-424M for 1080p. Without this level of interface, the resulting video will be degraded.
“All [FLIR] HD cameras have
native, high definition digital
components and outs.”
Unfortunately, some in the industry have used marketing tricks to create hybrid and analog systems that
manipulate the output to appear to be high definition,
but are lacking the necessary image data. Even so, these
systems are promoted as having HD capability.
At FLIR, when we say, real HD, we mean it. All our
HD cameras have native, high definition digital components and outputs, and we maintain that fidelity
throughout the system. FLIR doesn’t compress, resize,
or scale HD imagery, neither is the data file converted
to another format. The HD imagery stays digital from
its capture all the way to the output – same resolution,
uncompressed, clear and pristine all the way through.
In the real world, rescues and military operations don’t
just happen on bright sunlit days. Image quality is critical to mission success and crew safety, especially at
night and during heavy weather.
What Does High Definition
Mean For You?
The higher the resolution for the particular camera the
smaller and further away a target can be. There is a direct link between the number of pixels and the ability
to detect, recognize, and identify targets. Higher resolution thermal imaging provides finer detail and more
accurate results. With real HD components throughout
an HD thermal imaging system, users have more pixels on target, providing greater range and better overall
When considering the reasons images are captured,
whether for intelligence, surveillance, or reconnaissance, by moving to real HD systems, four to six times
more information is captured. This capability provides
more detail and enables cameras to see farther for
much stealthier operations.
For the military, this means seeing the target at a longer standoff range so that service-members don’t have
to go as far into harm’s way to complete a mission. For
search and rescue operations, HD enables responders
to search much wider areas more quickly – helping find
victims quicker. For law enforcement, HD enables a
wider, more detailed picture of subjects on the ground
without the ‘soda straw effect’ that happens when a traditional sensor is zoomed in.
Now That You Know
Having a basic understanding of what enables real HD
thermal capability enables users to be more discerning. When considering purchasing an HD thermal imaging system, savvy customers need to ask some very
1. What is the detector resolution of the focal plane
Anything less than a 640x512 focal plane array
(with optical microscanning) and 1280 x 720
resolution is not real HD quality.
The Star SAFIRE family of HD imaging systems is the first true family
of interchangeable and digital, high definition, single LRU imaging
systems providing a full spectrum of intelligence, surveillance, and
reconnaissance capabilities. Shown: Star SAFIRE 380-HD
2. Does the system use HD-capable lenses? What is the
line-pairs per millimeter (LP/mm) for the lens?
All lenses should resolve at a minimum of
80 LP/mm to achieve 720p resolution.
3. What quality interface does the system use?
Nothing less than an HD-SDI, SMPTE-292M interface should be used for a 720p HD system
A clear understanding of system components and resultant capabilities will result in a better application of
technology to a specific application.
For more information on HD thermal imaging
capabilities and requirements, contact a FLIR subject
FLIR Systems, Inc.
27700 SW Parkway Ave.
Wilsonville, OR 97070
PH: +1 800.727.3547
FLIR Systems, Inc.
25 Esquire Road
North Billerica, MA 01862
PH: +1 866.404.9920
FLIR Systems, Inc.
675 Discovery Drive
Huntsville, AL 35806
PH: +1 256.325.3547
FLIR Systems, Inc.
108 Kountz Lane
Freeport, PA 16229
FLIR Systems, Inc.
2800 Crystal Drive
Arlington, VA 22202
PH: +1 703.416.6666
FLIR Systems Ltd.
2 Kings Hill Avenue
West Malling, Kent
FLIR Systems Ltd.
5230 South Service Road
Burlington, ON L7L 5K2
PH: +1 800.613.0507
FLIR Systems AB
187 66 Täby
FLIR Systems Middle East
Dubai Airport Free Zone
P.O. Box 54262
United Arab Emirates